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Chemistry at the heart of that colorful fireworks display

June 30, 2017

John Schreifels

It’s fireworks that often characterize the Fourth of July, but George Mason University’s John Schreifels says its science that makes it so beautiful that it tugs at our hearts.

Schreifels, an associate professor within George Mason’s Chemistry and Biochemistry Department, says chemistry involving metal salts is what accounts for the many different shades of fireworks. Those commonly used in fireworks mean that we can expect to see red, white and blue and just about every other eye-catching color exploding into our nation’s skies during Independence Day celebrations.

“That transition of an electron from a high-energy state to a lower-energy state produces the change in colors,” Schreifels said. “The release of energy is the color coming out. The color depends on the compound you’re using.”

The process begins after the firework is lit and propelled into the sky. The explosive black powder confined inside the firework causes a dramatic increase of heat and gas that can send a firework skyward as high as 1,000 feet. A time-delay fuse burning slowly into the interior of the firework shell will go off once well into the sky, kindling a charge that reaches the core of the firework before exploding to ignite the metal salts.

Metal salts commonly used in firework displays include strontium carbonate (red fireworks), calcium chloride (orange fireworks), sodium nitrate (yellow fireworks), barium chloride (green fireworks) and copper chloride (blue fireworks). Purple fireworks are typically produced by use of a combination of strontium (red) and copper (blue) compounds.

Although Schreifels doesn’t exactly anticipate spectators rushing out to buy copies of the Periodic Table, he conceded that having one could actually come in handy.

“They might enjoy knowing a little bit about where the colors come from,” he said.

John Schreifels can be reached at jschreif@gmu.edu or 703-993-1082.

For more information, contact John Hollis at 703-993-8781 or jhollis2@gmu.edu.

About George Mason

George Mason University is Virginia’s largest public research university. Located near Washington, D.C., Mason enrolls 35,000 students from 130 countries and all 50 states. Mason has grown rapidly over the past half-century and is recognized for its innovation and entrepreneurship, remarkable diversity and commitment to accessibility.